Hi David,
The situation is as follows.
The IPTC's first priority is B2B News interchange. Support for
painless discovery of additional information about Taxonomies and
for the integration of News Taxonomies with the Semantic Web are
desirable goals but, for the IPTC, they come second. This
prioritisation relates both to the importance we attach to each
aspect, and to the order in which we are tackling them.
Now, the whole business of URI construction from tuples is a bit
of mess. XML Namespaces don't mandate such a mechanism. RDF does
require it, but the situation is difficult if many of the codes
start with a digit.
Given a code such as "123456", and given that we refuse to change
the code to, say, "_123456", the main legal choices before us
appear to be:
1. Simple concatenation using "/" as the delimiter
"http://www.iptc.org/NewsCodes/" & "123456" ->
"http://www.iptc.org/NewsCodes/123456"
2. Simple concatenation using "#_" as the delimiter
"http://www.iptc.org/NewsCodes#_" & "123456" ->
"http://www.iptc.org/NewsCodes#_123456"
3. Concatenation using "#_" as the delimiter, where the "_" is
glue, mandated by the relevant specification
"http://www.iptc.org/NewsCodes#" & "_" & "123456" ->
"http://www.iptc.org/NewsCodes#_123456"
4. Concatenation using "#_" as the delimiter, where the "#_" is
glue, mandated by the relevant specification
"http://www.iptc.org/NewsCodes" & "#_" & "123456" ->
"http://www.iptc.org/NewsCodes#_123456"
As we would very strongly prefer to end up with a Web page per
Taxonomy, containing a descriptive entry per concept, where the
constructed URI results in the relevant entry, we are not
enthusiastic about option 1.
That appears to leave options 2, 3 and 4. We have felt uneasy
about choosing between them without considered advice from the
SemWeb community.
As we are freezing the XML Schema for the News Architecture for our
G2 Standards next week, and hope to ratify it at our AGM in Tokyo
next month, this is an excellent time to consider and resolve the
question of how to build URIs for Taxonomies used in News.
We would very much welcome your input.
Misha Wolf
News Standards Manager, Reuters, http://www.reuters.com/
Vice Chair, News Architecture WP, IPTC, http://www.iptc.org/
-----Original Message-----
From: Booth, David (HP Software - Boston) [mailto:dbooth@hp.com]
Sent: 06 April 2007 17:12
To: Misha Wolf; Henry S. Thompson; www-tag@w3.org;
newsml-g2@yahoogroups.com
Subject: RE: Towards a TAG consideration of CURIEs
> From: www-tag-request@w3.org [mailto:www-tag-request@w3.org]
> . . .
> Henry pointed out at the Edinburgh AC meeting that if we used simple
> concatenation to give people access to information about terms in
> our taxonomies, we could end up with illegal fragment IDs. So:
>
> If:
> <subject qcode="iptc:123456"/>
> and if:
> iptc -> http://www.iptc.org/NewsCodes#
> and if we used simple concatenation, we'd get:
> iptc -> http://www.iptc.org/NewsCodes#123456
>
> There is, of course, the other option:
> iptc -> http://www.iptc.org/NewsCodes/
> then if we used simple concatenation, we'd get:
> iptc -> http://www.iptc.org/NewsCodes/123456
>
> We've decided to side-step this by specifying that the concatenation
> rules are taxonomy-specific and are up to the provider of each
> taxonomy.
So any URI-based program using multiple taxonomies must have special
concatenation rules built in for *each* taxonomy? That sounds awful.
Was there some reason why the group could at least recommend that the
namespace part end with either "/" or "#" (along with corresponding
constraints on the local part)?
David Booth, Ph.D.
HP Software
+1 617 629 8881 office | dbooth@hp.comhttp://www.hp.com/go/software
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